Recording medium recording and/or reproduction apparatus, recording and/or reproduction method

ABSTRACT

A method for reproducing a recording medium comprising reading out identification data from a recording medium having recorded thereon data and the identification data, which identification data includes entity identification data and detection data. The detection data is generated using at least the entity identification data and indicates whether or not the entity identification data at least is authentic data. The identification recorded on the recording medium is read out, detection data is generated based on the entity identification data of the identification data as read out and the detection data extracted from the read-out identification data is compared to the generated detection data. When, as a result of comparison, the detection data extracted from the read-out identification data is coincident with the generated detection data, the outputting of the data read out from the recording medium is permitted.

TECHNICAL FIELD

This invention relates to a method and an apparatus for a recordingmedium on which are recorded contents data downloaded over a network.

BACKGROUND ART

There is a contents distributing system for distributing contents data,such as music, over the network, such as EMD (electronic musicdistribution). With this system, a user terminal device, for example,may access a server device, where the contents data are stored, todownload desired contents data. For payment, the private information,such as a credit card number, a secret number or the Web money, is sentfrom the user terminal device to the server device.

In such system, payment is by transmitting the private information, suchas credit card number, secret number or the Web money from the terminaldevice to the server device, over the network, so that a cumbersomeoperation is needed in inputting the private information. Moreover,there is a risk that the private information may be illicitly acquiredby a third party for unauthorized use.

As a means for combating this problem, there is a payment systememploying a pre-paid recording medium. In this system, the remainingrecordable volume of the contents data is recorded on the recordingmedium purchased by the user. When the terminal device accesses a serverdevice to download the contents data desired by the user, dataindicating the recordable volume is transmitted from the terminal deviceto the server device. The terminal device receives the downloadedcontents data and the updated data indicating the recordable data volumeto record these data on the recording medium.

With the recording medium used in this system, the contents data and thedata indicating the recordable data volume need to be updated from timeto time, and hence the write-once or rewritable recording medium isused. Consequently, the recordable data volume, recorded on therecording medium, may be manipulated by a user with a malignantintention, as a result of which the contents data may be repeatedlydownloaded by the user with a malignant intention, thus detracting fromthe benefit of the system supervisor or the copyright owner.

DISCLOSURE OF THE INVENTION

It is therefore an object of the present invention to provide arecording medium a data recording and/or reproducing method and a datarecording and/or reproducing apparatus, whereby the contents data may beprotected to protect the benefit of the system manager supervising thecontents data and the copyright owner of the contents data.

It is another object of the present invention to provide a recordingmedium a data recording and/or reproducing method and a data recordingand/or reproducing apparatus, whereby it is possible to prohibitmanipulation of e.g., the recordable data volume.

In one aspect, the present invention provides a method for reproducing arecording medium including reading out identification data from arecording medium, having recorded thereon data and identification data,the identification data including entity identification data anddetection data, the detection data being generated using at least theentity identification data, the detection data indicating whether or notthe entity identification data at least is authentic data. The methodalso includes generating detection data based on the identification dataread out, comparing detection data extracted from the read-outidentification data to the generated detection data, and permitting theoutputting of the data read out from the recording medium when theresults of comparison indicate the coincidence of the detection dataextracted from the read-out identification data with the generateddetection data.

In another aspect, the present invention provides an apparatus forreproducing a recording medium including a head unit for scanning arecording medium having recorded thereon data and identification data,the identification data including entity identification data anddetection data, the detection data being generated using at least theentity identification data, the detection data indicating whether or notthe entity identification data at least is authentic data. The apparatusalso includes a signal processing unit for performing signal processingfor reproducing an output signal from the head unit, a generating unitfor generating detection data based on the entity identification data ofthe identification data read out from the recording medium, a comparatorfor comparing detection data extracted from the identification data readout to detection data generated by the generating unit, and anoutputting unit supplied with output data from the signal processingunit for limiting the outputting of the output data from the signalprocessing unit by output data derived from the results of comparisonfrom the comparator.

In still another aspect, the present invention provides a method forrecording a recording medium, in which the method includes transmittingidentification data read out from a recording medium, having recordedthereon the entity identification data, data indicating the volume ofrecordable data, and detection data, which detection data is generatedusing the entity identification data and the recordable data volumeindicating data, and indicates whether or not at least the entityidentification data and the recordable data volume indicating data areauthentic data. The method also includes recording the identificationdata including updated recordable data volume indicating data,transmitted along with contents containing data, on the recordingmedium.

In still another aspect, the present invention provides a data recordingand/or reproducing method including reading out identification data froma recording medium having recorded thereon identification data, theidentification data including entity identification data and detectiondata, the detection data being generated using at least the entityidentification data, the detection data indicating whether or not theentity identification data at least is authentic data. The method alsoincludes transmitting the read-out data and selection data to a serverdevice holding plural data, the server device generating detection databased on the entity identification data of the identification data,comparing the so generated detection data and detection data extractedfrom the transmitted identification data, the server device reading outand transmitting data corresponding to the selection data in case ofcoincidence of the generated detection data and the detection dataextracted from the transmitted identification data, and recording thetransmitted data on or reproducing the transmitted data from therecording medium, on the recording medium.

In still another aspect, the present invention provides a recordingmedium including a data recording area where data is recorded, and amanagement data area where there is recorded identification datainclusive of entity identification data and detection data generatedusing at least the entity identification data. The detection dataindicates whether or not the entity identification data at least isauthentic data.

The identification data includes data indicating the volume of datarecordable on the recording medium, along with the entity identificationdata, and the detection data generated is generated based on the entityidentification data and on the data indicating the volume of recordabledata.

In yet another aspect, the present invention provides a recording and/orreproducing apparatus for a recording medium, in which the apparatusincludes a head unit for scanning the recording medium having recordedthereon identification data, the identification data including entityidentification data and detection data, the detection data beinggenerated using at least the entity identification data and indicatingwhether or not the entity identification data at least is authenticdata. The apparatus also includes a signal processing unit forperforming signal processing for reproducing an output signal from thehead unit, a communication unit for transmitting the identification dataread out from the head unit and selection data and for receivingtransmitted data corresponding to the selection data, a generating unitfor generating the detection data based on the entity identificationdata of the identification data read out from the recording medium, acomparator unit for comparing the detection data extracted from theread-out identification data and the detection data generated by thegenerating unit, an outputting unit supplied with the output data fromthe signal processing unit and adapted for controlling the outputting ofthe output data from the signal processing unit by output data derivedfrom the results of comparison from the comparator and a recordingsignal processing unit for performing signal processing of recording thedata corresponding to the selection data received via the communicationunit on the recording medium to send the processed data to the headunit.

Other objects, features and advantages of the present invention willbecome more apparent from reading the embodiments of the presentinvention as shown in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a downloading system for contents data embodying thepresent invention.

FIG. 2 is a perspective view for illustrating an optical disc employedin the system shown in FIG. 1.

FIG. 3 illustrates PUID data recorded in a management area of theoptical disc.

FIG. 4 illustrates PUID data generated by a hash function.

FIG. 5 is a block diagram for illustrating a data recording apparatusfor recording PUID data thereon.

FIG. 6 is a block diagram for illustrating an exemplary structure of aunit for generating MDC data.

FIG. 7 is a block diagram for illustrating another exemplary structureof a generating unit for generating MDC data.

FIG. 8 is a block diagram for illustrating still another exemplarystructure of a unit for generating MDC data.

FIG. 9 is a block diagram for illustrating a server device.

FIG. 10 is a block diagram for illustrating a unit for updating MDCdata.

FIG. 11 is a block diagram for illustrating a data recording and/orreproducing apparatus.

FIG. 12 is a flowchart for illustrating the sequence of operations untila user downloads and reproduces desired contents data.

FIG. 13 illustrates another PUID recorded in a management area of theoptical disc.

FIG. 14 illustrates another PUID recorded in a management area of theoptical disc.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the drawings, an optical disc, a method and an apparatusfor recording data on this optical disc and a method and an apparatusfor reproducing data from the optical disc, according to the presentinvention, will be explained in detail.

The present invention is applied to a system for distributing contentsdata, such as music, over the network, such as EMD (electronic musicdistribution). In this contents data distribution system 1, shown inFIG. 1, a user purchases a write-once or rewritable optical disc, onwhich can be recorded the contents data, accesses a server device 40,over a network, by a data recording and/or reproducing device 60 he/sheowns, downloads the desired contents data from a server position, andrecords the downloaded contents data on the purchased optical disc 10.That is, the present system 1 is of a pre-paid system un which the pricefor the user to download contents data is paid at the time of purchasingthe optical disc 10 on which to record the contents data.

In this optical disc 10, used in the system 1, there is pre-recordeddata indicating the recordable volume of the contents data. This dataindicating the recordable volume is e.g., such data indicating that 1000yen equivalent of contents data or 10-minute equivalent of contents datacan be recorded. If, for downloading contents data to the optical disc10, the user's recording and/or reproducing device 60 accesses theserver device 40, the user's recording and/or reproducing devicetransmits the data on the recordable volume, recorded on the opticaldisc 10, along with a contents data download request, to the serverdevice 40, and receives the corresponding contents data and data on theremaining recordable data volume, updated by the server device 40, torecord the contents data and the data on the remaining recordable datavolume on the optical disc 10.

If the optical disc 10, used for the present system 1, is a write-oncedisc, a layer of an organic dye material, as a recording layer, isprovided on one surface of a light transmitting disc substrate, carryinga pattern of lands and grooves, on this surface, whereas, if the opticaldisc is a rewritable disc, a layer of a phase change material isprovided as a recording layer, as shown in FIG. 2. On this recordinglayer are sequentially formed a reflective layer and a protective layer.A light beam is illuminated from the disc substrate side for recordingand/or reproducing information signals.

This optical disc 10 has a center opening 11 around which is formed amanagement area 12 for recording management data. On the outer rim sideof the management area 12 is formed a data recording area 13 in which torecord contents data.

In the management area 12, there is recorded prepaid unique ID data,referred to below as PUID data, as management data for supervising therecording of contents data, as shown in FIG. 3. This PUID data is madeup by unique ID data for identifying each distributed optical disc 10,referred to below as UID data, PA (prepaid amount) data, indicating aprepaid amount, for specifying the recordable volume data, amanipulation/modification detection code, referred to below as MDC data,as authenticity data for detecting whether or not the UID data and PAdata have been manipulated.

The UID data is a unique identification data, accorded to each of theoptical discs 10 distributed, for discriminating the distributed opticaldisc 10. Specifically, the UID data has 44 bytes, for example, allocatedthereto, and is made up by at least one data from among a nation number,a company number, a plant number, a license number and serial number.The PA data has four bytes, for example, allocated thereto, and is madeup by at least one data from among a recordable time of the contentsdata, number of recordable titles, and data on e.g., amounts prepaid atthe time of purchasing the optical disc, such as 1000 yen, 2000 yen or3000 yen, in a data recording area 13 reserved for the cost of theoptical disc. Of course, the data forming the PA data may be constitutedby one or more of these data.

The MDC data is a code of for example 8 or 16 bytes for verifyingwhether or not the UID data or PA data has been modified, as shown inFIG. 4. It is generated from the UID data and PA data, using a hashfunction, as a unidirectional function, and is able to detect whether ornot the UID data or PA data has been modified by e.g., manipulation.Thus, with the present optical disc 10, the MDC data, pre-recorded inthe management area 12, is compared to the MDC data, generated at thetime of recording and/or reproduction from the UID data and PA data,using a hash function, when the user downloads desired contents datafrom the server device 40 using the data recording and/or reproducingapparatus 60 or when the user reproduces contents data downloaded fromthe server device 40. The contents data may be recorded and/orreproduced only when the two coincide, so that there is no risk ofcontents data being recorded and/or reproduced by an unauthorized user.

As authenticity data, MAC (Message Authentication Data) may be used inplace of the MDC data. Alternatively, CRC (cyclic redundancy check code)may be used. With CRC, it is possible to specify manipulated portions ofthe UID data or PA data.

The optical disc 10, constructed as described above, is sold in e.g., anaudio store with the PUID data recorded in the management area 12thereof.

Referring to FIG. 5, a data recording apparatus 20, used for recordingPUID data on the above-described optical disc 10, is owned by e.g., anaudio producing firm, and includes a generating unit 21, a multiplexer22, an error correction encoding unit 23, a modulating unit 24, arecording processing unit 25, an optical pickup 26, a motor 27, and aservo controlling unit 28. The generating unit 21 is supplied with UIDdata and PA data to generate PUID data using a hash function. Themultiplexer 22 generates PUID data made up by the UID data, PA data andthe MDC data. The error correction encoding unit 23 appends errorcorrection codes to the PUID data. The modulating unit 24 modulated dataprocessed with error correction encoding. The recording processing unit25 executes processing for recording the PUID data in the managementarea 12 of the optical disc 10. The optical pickup 26 radiates a lightbeam to the optical disc 10 for recording the PUID data to detect thereturn light beam. The motor 27 runs the optical disc 10 in rotation atCLV (constant linear velocity) or at CAV (constant angular velocity).The servo controlling unit 28 performs focussing control or trackingcontrol of the optical pickup 26 and rotational control of the motor 27.

The generating unit 21 is supplied with UID data, PA data and with aninitial value from a first input terminal 29, a second input terminal 30and from a third input terminal 31, respectively. Referring to FIG. 4,the generating unit 21 generates MDC data from the UID data and from thePA data, using the hash function, to output the resulting MDC data tothe multiplexer 22.

The generating unit 21, generating the MDC data, using the hashfunction, is explained in detail.

If the hash function is e.g., a so-called Modified Davies-Meyer, thegenerating unit 21 includes a block encrypting circuit 33, for executingthe block encryption exhibiting chaining properties, as shown in FIG. 6.This block encrypting circuit 33 exploits e.g., encryption conforming tothe data encryption standard, referred to below as DES, and is suppliedwith the UID data made up by 44 bytes and with PA data made up by 4bytes, as plaintext data Mi (i=1 to 6 (=(44+4)×8/64)), in terms of ablock made up by 64 bits as a unit.

With a value of e.g., 64 bits, generated at random (referred to below asa random initial value H₀), as initial encryption key data, the blockencrypting circuit 33 encrypts the plaintext data M_(i), as an initialblock, with DES, to output cryptotext data H₁. The block encryptingcircuit 33 then DES-encrypts the plaintext data M₂, as the next block,with the produced cryptotext data H₁ as encryption key data to outputcryptotext data H₂. In similar manner, the block encrypting circuit 33DES-encrypts the plaintext data M_(i), with the cryptotext data H_(i−1),obtained by the previous encryption, as encryption key data, to encryptthe plaintext data M_(i). This sequence of operations is repeated up toplaintext data M₆. That is, the generating unit 21 repeatedly executesthe calculations according to the following equations:H ₀ =I _(H)(random initial value)H _(i) =E _(Hi−1) ,M _(i)(H _(i−1))where E_(Hi−1) denotes encryption employing the cryptotext data H_(i−1)as encryption key data. The cryptotext data H₆, ultimately obtained, issent to the multiplexer 22 as MDC data. In decryption, the processingsimilar to that described above is performed repeatedly on the UID dataand the PA data, recorded in the management area 12 of the optical disc10, using the random initial value H₀ as encryption key data. The soproduced cryptotext data is compared to the cryptotext data H₆, recordedas the MDC data on the optical disc 10, to check to see whether the HIDdata and/or the PA data have been manipulated.

The generating unit 21 may be constructed as shown in FIG. 7. In thepresent embodiment, the hash function is, for example, a so-calledTandem Davies-Meyer, with the generating unit 21 including two blockencryption circuits 34, 35, performing block encryption exhibitingchaining properties, and two exclusive-OR circuits 36, 37, adapted forfinding an Ex-OR of the encryption key data and the cryptotext data, asshown in FIG. 7. These block encryption circuits 34, 35 use DESencryption, for example, and are supplied with 44 bytes of the UID dataand 4 bytes of the PA data, on the block basis, with e.g., 64 bits asone block, in the form of plaintext data M_(i) (i=1 to 6(=(44+4)×8/64)).

The block encryption circuit 34 DES-encrypts the plaintext data Mi, asan initial block, with e.g., 64 bits of the random initial value G₀generated at random, as an initial encryption key data, to outputcryptotext data W_(i). The exclusive-OR circuit 36 finds Ex-OR of arandom initial value H₀, different than the random initial value G₀, andthe cryptotext data W_(i), to output the result as cryptotext data H₁.On the other hand, the block encryption circuit 35 DES-encrypts thecryptotext data W_(i), output from the block encryption circuit 34, withthe plaintext data Mi as initial encryption key data, whilst theexclusive-OR circuit 37 finds the Ex-OR of the random initial value G₀and the output of the block encryption circuit 35 to output the resultas cryptotext data G₁.

The block encryption circuit 34 DES-encrypts the plaintext data M₂, asthe next block, with the cryptotext data G₁, output from theexclusive-OR circuit 37, as encryption key data, to output cryptotextdata W₂. The exclusive-OR circuit 36 finds an Ex-OR of the cryptotextdata H₁, output from the exclusive-OR circuit 36, and the cryptotextdata W₂, to output the result as cryptotext data H₂. The blockencryption circuit 35 DES-encrypts the cryptotext data W₂, output fromthe block encryption circuit 34, with the plaintext data M₂ asencryption key data, whilst the exclusive-OR circuit 37 finds an Ex-ORof the cryptotext data G₁ and an output of the block encryption circuit35 to output the result as cryptotext data G₂.

In similar manner, the block encryption circuit 34 DES-encrypts theplaintext data M_(i), with cryptotext data Gi−1, obtained by theprevious encryption, as encryption key data, whilst the exclusive-ORcircuit 36 finds the Ex-OR of the cryptotext data H_(i−1) and thecryptotext data W_(i) to output the result as cryptotext data H_(i). Theblock encryption circuit 35 DES-encrypts the cryptotext data W_(i), withthe plaintext data M_(i) as encryption key data, whilst the exclusive-ORcircuit 37 finds the Ex-OR of the cryptotext data G_(i−1) and the outputof the block encryption circuit 35 to output the result as cryptotextdata G_(i). This sequence of operations is reiterated up to theplaintext data M₆. That is, the generating unit 21 reiterates thecalculations of the following equations:G ₀ =I _(G)(random initial value)H ₀ =I _(H)(another random initial value)W _(i) =E _(Gi−1,Mi)(H _(i−1))G _(i) =G _(i−1) ⊕E _(Mi,wi)(G _(i−1))H _(i) =W _(i) ⊕H _(i−1)where E_(Gi−1) depicts encryption with the cryptotext data G_(i−1) asencryption key data and E_(Mi) depicts encryption with the plaintextdata M_(i) as encryption key data. The generating unit 21 generates,from the ultimately obtained cryptotext data G₆ and H₆, a differentialG₆−H₆, which then is output to the multiplexer 22.

In an alternative structure of the generating unit 21, the hash functionis e.g., what is called the CBC-MAC (Cipher-Block-Chaining-MessageAuthentication Code). The generating unit 21 includes a block encryptingcircuit 38, for performing block encryption exhibiting chainingproperties, and an exclusive-OR circuit 39 for finding the Ex-OR of thecryptotext data and the plaintext data, as shown in FIG. 8. This blockencrypting circuit 38 exploits e.g., encryption, and is supplied withthe UID data made up by 44 bytes and with PA data made up by 4 bytes, onthe block basis, in the form of plaintext data M_(i) (i=1 to 6(=(44+4)×8/64)), in terms of a block made up by e.g., 64 bits as oneblock.

The exclusive-OR circuit 39 is supplied with a random initial value IV(≠0), as an initial value, and finds an Ex-OR thereof with the plaintextdata M_(i) to output the result to the block encryption circuit 38. Theblock encryption circuit 38 DES-encrypts an initial block, using anoutput from the exclusive-OR circuit 39 as secret key, to outputcryptotext data Hi.

The exclusive-OR circuit 39 then finds an Ex-OR of the so producedcryptotext data H_(i) and plaintext data M₂, as the next block, tooutput the result to the block encryption circuit 38. This blockencryption circuit 38 DES-encrypts the output, using a secret key, tooutput cryptotext data H₂. In similar manner, the generating unit 21DES-encrypts the plaintext data M_(i), using the cryptotext dataH_(i−1), obtained by the previous encryption, as encryption key data.This sequence of operations is repeated up to the plaintext data M₆. Thecryptotext data H₆, thus obtained, is output as MAC data to themultiplexer 22.

In the above-described embodiment, the block size for block encryption,for example, is set to 64 bits. The present invention is not limited tothis specified embodiment, such that the block size may be differentthan 64 bits. With the block size of, for example, 128 bits, the MDCdata is the cryptotext data H₃, obtained on three encryption operations,or a differential of the cryptotext data G₃–H₃.

Referring to FIG. 5, the multiplexer 22 is supplied with the UID data,PA data and with the MDC data, from the first input terminal 29, asecond input terminal 30 and from the generating unit 21, respectively.The multiplexer 22 synthesizes the UID data, PA data and the MDC datatogether to generate the PUID data to be recorded on the optical disc 10to output the PUID data to the error correction encoding unit 23.

The error correction encoding unit 23 applies encoding, by a combinationof cross-interleaving and order-four Reed Solomon codes, to samples ofthe digital data, using an algorithm of cross-interleave Reed-SolomonCode (CIRC), to output the result to the modulating unit 24, as shown inFIG. 5. The modulating unit 24 modulates the encoded output data fromthe error correction encoding unit 23, in accordance with an EFM(eight-to-fourteen modulation), to output the modulated result to therecording processing unit 25. This recording processing unit 25 performspreset recording processing on the modulated data to output the resultto the optical pickup 26.

The optical pickup 26 includes a semiconductor laser device, forradiating laser light as a laser light beam, an objective lens forcondensing the light beam, radiated from the semiconductor laser device,and a photodetector for detecting the return light beam reflected backfrom the optical disc 10. The optical pickup 26 illuminates the lightbeam, radiated from the semiconductor laser device, to the signalrecording surface of the optical disc 10, to record data, such as PUIDdata, on the recording surface, while detecting the return light beam,reflected back from the signal recording surface of the optical disc 10,by the photodetector. The objective lens is held by an objective lensdriving mechanism, such as electromagnetic actuator, and is moved alongthe focussing direction, parallel to the optical axis of the objectivelens, based on focussing servo signals, while being moved along thetracking direction perpendicular to the optical axis of the objectivelens, based on the tracking servo signals.

The servo controlling unit 28 is supplied, from an error signalgenerating unit, not shown, with focussing error signals and withtracking error signals, generated from output signals of a photodetectorforming the optical pickup 26. For example, the focussing error signalsare generated by the so-called astigmatic method, while the trackingerror signals are generated by a so-called three-beam method or apush-pull method. The servo controlling unit 28 generates focussingservo signals, based on the supplied focussing error signals, so thatthe focussing error signals will be reduced to zero. The servocontrolling unit 28 also generates tracking servo signals, based on thesupplied tracking error signals, so that the tracking error signals willbe reduced to zero. The servo controlling unit 28 outputs the focussingservo signals and tracking servo signals to a driving circuit, notshown, of the objective lens driving mechanism forming the opticalpickup 26. This driving circuit actuates the objective lens drivingmechanism, based on the focussing servo signals, to move the objectivelens along the focussing direction parallel to the optical axis of theobjective lens. The driving circuit also actuates the objective lensdriving mechanism, based on the tracking servo signals, to move theobjective lens along the tracking direction perpendicular to the opticalaxis of the objective lens.

The sequence of operations of the data recording apparatus 20, adaptedfor recording the PUID data in the management area 12 of the opticaldisc 10, is hereinafter explained. First, the UID data of the opticaldisc 10, on which to record the PUID data, is input to the first inputterminal 29. The PA data, indicating the volume of the contents datarecordable on the optical disc 10, on which is recorded the PUID data,is input to the first input terminal 30. The generating unit 21generates the MDC data, using the hash function, from the UID data inputfrom the first input terminal 29 and from the PA data input from thesecond input terminal 30, to output the so generated data to themultiplexer 22. The multiplexer 22 synthesizes the UID data, PA data andthe MDC data, supplied from the first input terminal 29, to generatePUID data to be recorded in the management area 12, to output the sogenerated PUID data to the error correction encoding unit 23. This errorcorrection encoding unit 23 appends error correction codes to the PUIDdata. The modulating unit 24 then modulates the PUID data added by theerror correction code. The recording processing unit 25 then performsrecording processing to output the resulting data to the optical pickup26. The optical pickup 26 illuminates a light beam on the managementarea 12 of the rotating optical disc, loaded on the disc table, formingthe disc rotating driving mechanism, to record the PUID data in themanagement area 12. The servo controlling unit 28 exercises focussingservo control and tracking servo control of the objective lens in orderto record the PUID data reliably in the management area 12.

It is noted that the present system 1 is made up by a server device 40,owned by a provider, superintending the present services, and a datarecording and/or reproducing device 60, owned by e.g. a user. Thesedevices are interconnected over a network, such as ISDN (IntegratedServices Digital Network), CATV (Cable television) network, opticalcable network or a satellite network, and are capable of exchanging datain accordance with a transmission protocol, such as TCP/IP (transmissioncontrol protocol/Internet protocol) or FTP (file transfer protocol).

Referring to FIG. 9, the server device 40, owned by a provider,superintending the present services, includes, for example, a storageunit 41, in which is stored contents data, downloaded from the recordingand/or reproducing device 60, owned by the user, a readout detectionunit 42, for reading out preset contents, from the storage unit 41, acommunication unit 43 for communication with the recording and/orreproducing device 60, owned by the user, a demultiplexer 44 forseparating the PUID data, transmitted from the recording and/orreproducing device 60, owned by the user, a generator 45 for generatingthe MDC data, from the UID data and the PA data, and a comparator 46 forcomparing the MDC data extracted by the demultiplexer 44 from the PUIDdata to the MDC data generated by the generator 45. The server device 40also includes an update unit 47 for updating the PUID data ondownloading the contents data, and a discrimination unit 48 forverifying whether or not the contents data specified by the user can bedownloaded with the current PA data.

The storage unit 41 is made up by for example a large capacity hard discdrive device, and has stored therein contents data exemplified by musicnumber data or motion picture data. It is noted that the contents dataare recorded encoded by compression encoding methods, exemplified byATRAC 3 (Adaptive Transform Acoustic Coding 3: trademark). MPEG-2AAC(Moving Picture Expert Group 1 Advanced Audio Coding: trademark), MP3(MPEG-1 Audio Layer 3, trademark), TwinVQ (Transform-Domain WeightedInterleave Vector Quantization, trademark), MS Audio (WMA: WindowsMediaAudio: trademark) and Ogg Vorbis (trademark). The readout detectionunit 42 retrieves contents data, which is in keeping with selection datafor selecting the contents data, transmitted from the recording and/orreproducing device 60, owned by the user, and reads out the retrieveddata from the storage unit 41.

The communication unit 43 receives data, such as download request fromthe user's recording and/or reproducing device 60, selection data forthe contents data, transmitted from the recording and/or reproducingdevice 60, or the PUID data, recorded on the optical disc 10, loaded onthe user's recording and/or reproducing device 60. The communicationunit 43 sends data, such as contents data, which is in keeping with theselection data, or updated UID data, to the recording and/or reproducingdevice 60.

The demultiplexer 44 demultiplexes the PUID data, input from thecommunication unit 43, into the UID data, PA data and MDC data, androutes the UID data and the PA data to the generating unit 45 and to theupdate unit 47. The demultiplexer 44 also routes the PA data to thediscrimination unit 48 for updating the recordable data volume.Moreover, the demultiplexer 44 outputs the MDC data to the comparator46.

The generating unit 45 generates the MDC data, from the UID data and thePA data, input from the using the demultiplexer 44, using the hashfunction, to output the so generated MDC data to the comparator 46.Meanwhile, the generating unit 45 is similar in structure to theconfiguration shown in FIGS. 6 to 8 and hence is not explainedspecifically.

The comparator 46 compares the MDC data, extracted from thedemultiplexer 44, to the MDC data, generated by the generating unit 45,to make a check as to possible coincidence between these MDC data. Thatis, if the UID data or the PA data has been manipulated, the MDC datagenerated by the generating unit 45 differs from the MDC data extractedby the demultiplexer 44. Thus, the comparator 46 compares the MDC data,extracted by the demultiplexer 44, to the MDC data, generated by thegenerating unit 45 and, in case of coincidence of these two MDC data,determines that the access is that from an authorized user, to output areadout permission signal to the readout detection unit 42. In case ofnon-coincidence of the extracted MDC data with the generated MDC data,the comparator determines the access to be that from an unauthorizeduser to output a readout inhibit signal to the readout detection unit42.

When transmitting contents data, which is in keeping with the selectiondata, to the data recording and/or reproducing device, the update unit47 updates the PA data and, using the hash function, generates the PUIDdata, to be transmitted to the data recording and/or reproducing device60, from the updated PA data and the UID data. Specifically, the updateunit 47 includes a generating unit 51, supplied with the UID data andthe PA data to generate the MDC data with the aid of the hash function,and a multiplexer 52 for generating the PUID data made up by the UIDdata, PA data and the MDC data, as shown in FIG. 10. The generating unit51 is supplied with the UID data, updated PA data and with an initialvalue from the first input terminal 53, a second input terminal 54 andfrom a third input terminal 55, respectively. The generating unit 51generates MDC data, using the hash function, from the UID data and theupdated PA data, to output the so generated MDC data to the multiplexer52. That is, the generating unit 51 is supplied with a value equal tothe current recordable value less a value corresponding to the numbertransmitted to the data recording and/or reproducing device 60, as PAdata, and generates MDC data from the PA data and the UID data.Meanwhile, the configuration of the generating unit 51 is the same asthat of FIGS. 6 to 8 and hence is not explained in detail. Themultiplexer 52 is supplied with the UID data, updated PA data and withthe updated MDC data, from the first input terminal 53, second inputterminal 54 and from the generating unit 51, respectively. Themultiplexer 52 synthesizes the UID data, PA data and the MDC data togenerate updated PUID data to be recorded on the optical disc 10, asshown in FIG. 3. The update unit 47, shown in FIG. 9, constructed asdescribed above, performs error correction and modulation processing onthe PUID data to output the resulting data to the communication unit 43.

Referring to FIG. 9, the discrimination unit 48 verifies whether or notthe contents data specified by the user can be downloaded with thecurrent PA data. If the current PA data does not meet the condition fordownloading the desired contents data, the discrimination unit 48outputs a readout inhibit signal, inhibiting the readout of the contentsdata, to the readout detection unit 42, whereas, if the current PA datais sufficient to download the desired contents data, the discriminationunit 48 outputs a readout permission signal to the readout detectionunit 42. The ‘current PA data does not meet the condition fordownloading the desired contents data’ if for example the amount fordownloading the contents data cannot be collected, or if the recordablecapacity falls short.

The operation of the server device 40, constructed as described above,is now explained. If the PUID data is transmitted, along with theselection data for the contents data, from the user's data recordingand/or reproducing device 60, the communication unit 43 outputs the PUIDdata to the demultiplexer 44, while outputting the selection data to thereadout detection unit 42. The demultiplexer 44 separates the PUID data,input from the communication unit 43, into the UID data, PA data and theMDC data, and outputs the MDC data to the comparator 46, whileoutputting the UID data and the PA data to the generating unit 45 and tothe update unit 47. The demultiplexer 44 outputs the PA data to thediscrimination unit 48 for determining the recordable volume. Thegenerating unit 45 generates MDC data, from the UID data and the PAdata, supplied from the demultiplexer 44, using the hash function, tooutput the MDC data to the comparator 46. Before reading out thecontents data corresponding to the selection data, the comparator 46 hasto verify whether or not the access is from the data recording and/orreproducing device 60 of a user owning the authentic optical disc 10. Tothis end, the comparator 46 compares the MDC data, supplied from thedemultiplexer 44, to that supplied from the generating unit 45, to checkto see if the two coincide with each other. The reason is that, if thePA data indicating the possible recording volume has been changed, theMDC data, output by the generating unit 45, differs from the MDC dataextracted by the demultiplexer 44. The comparator 46 compares the MDCdata generated in the generating unit 45 to the MDC data extracted bythe demultiplexer 44. In case of coincidence of the two data, thecomparator 46 is able to determine that the access is from the datarecording and/or reproducing device 60 of an authorized user and, ifotherwise, the comparator 46 is able to determine that the access isfrom the data recording and/or reproducing device 60 of an unauthorizeduser. In case of coincidence of the extracted MDC data to the generatedMDC data, the comparator 46 outputs a contents data readout permissionsignal to the readout detection unit 42. In case of non-coincidence ofthe extracted MDC data to the generated MDC, the comparator 46 outputs acontents data readout inhibit signal to the readout detection unit 42.The discrimination unit 48 verifies whether or not the contents dataspecified by the user can be downloaded with the current PA data. If theresults of discrimination indicate that the downloading is possible, thediscrimination unit 48 outputs a readout permission signal to thereadout detection unit 42, whereas, if the PA data is not up to therequirements, for example, if the PA data is in shortage, thediscrimination unit 48 outputs a readout inhibit signal to the readoutdetection unit 42.

When the readout detection unit 42 is supplied with the reproductionpermission signal from the comparator 46 and from the discriminationunit 48, the readout detection unit 42 retrieves and extracts thecontents data corresponding to the selection data input from thecommunication unit 43 from the plural contents data stored in thestorage unit 41, to output the retrieved and extracted contents data tothe communication unit 43. Simultaneously, the update unit 47 updatesthe PA data, responsive to e.g., the number of downloaded items of thecontents data and, using the updated PA data, UID data and the MDC data,generates the PUID data to be transmitted to the data recording and/orreproducing device 60, and outputs the so generated PUID data to thecommunication unit 43. This communication unit 43 sends the updated PUIDdata, along with the contents data corresponding to the selection data,to the user's data recording and/or reproducing device 60. Thus, theserver device 40 is able to prohibit contents data from beingtransmitted to the data recording and/or reproducing device 60 of anunauthorized user by verifying, with the aid of the MDC data of the PUIDdata transmitted from the user's data recording and/or reproducingdevice 60, whether or not an access is from an authorized user.Moreover, the server device 40 is able to prohibit manipulation of thePUID data by the user, by server device 40 updating the PUID data and bythe data recording and/or reproducing device 60 not updating the PUIDdata.

Referring to FIG. 11, the data recording and/or reproducing device 60,accessing the server device 40, is now explained. This data recordingand/or reproducing device 60 includes a motor 61 for rotationallydriving the optical disc 10, an optical pickup 62 for recording and/orreproducing data by illuminating a light beam on the optical disc 10, anRF amplifier 63 for amplifying an output from the optical pickup 62, aservo controlling unit 64 for servo controlling the motor 61 and theoptical pickup 62, a communication unit 65 for receiving PUID data orcontents data, transmitted from the server device 40, a recordingprocessor 66 for performing recording processing on the data received bythe communication unit 65, a demodulating unit 67 for demodulating anoutput from the RF amplifier 63, an error correction decoding unit 68for performing error correction processing on the data demodulated bythe demodulating unit 67, a demultiplexer 69 for separating the PUIDdata into the UID data, PA data and the MDC data, a generating unit 70for generating MDC data from the UID data and the PA data, a comparator71 for comparing the MDC data extracted by the demultiplexer 69 from thePUID data, to the MDC data generated by the generating unit 70, and aD/A converter 72 for converting the contents data from digital signalsto analog signals. The data recording and/or reproducing device 60 alsoincludes a switching unit 73 for limiting the outputting to the D/Aconverter, and an output unit 74, such as a loudspeaker or a monitor,for outputting contents data.

The distal end of a rotational shaft of the motor 61 carries a disctable, adapted for loading the optical disc 10 thereon, so that theoptical disc 10 loaded on the disc table is run in rotation in CLV orCAV, under control by the servo controlling unit 64.

The optical pickup 62 includes a semiconductor laser device, radiatingthe laser light as a light beam, not shown, an objective lens forcondensing the light beam, radiated from the semiconductor laser device,on the recording layer of the optical disc 10, and a photodetector fordetecting the return light beam reflected back from the optical disc 10.When recording the PUID data or the downloaded contents data, theoptical pickup 62 illuminates the light beam, radiated from thesemiconductor laser device, on the recording layer of the optical disc10, to record data, such as PUID data, on the recording layer. Duringreproduction, the optical pickup 62 illuminates the light beam to apreset area to detect the return light beam, reflected back from therecording layer, by a photodetector, by way of photoelectricallytransducing the light beam. The objective lens, held by an objectivelens driving mechanism, such as electromagnetic actuator, is drivenalong the focussing direction parallel to the optical axis of theobjective lens, based on the focussing servo signal, while being drivenalong the tracking direction, perpendicular to the optical axis of theobjective lens, based on the tracking servo signals. The optical pickup62 scans the optical disc 10 by being moved along the radius of theoptical disc 10, by a feed mechanism, not shown.

Based on an output signal from a photodetector, forming the opticalpickup 62, the RF amplifier 63 generates RF signals, focussing errorsignals and tracking error signals. The focussing error signals aregenerated by a so-called astigmatic method, whilst the tracking errorsignals are generated by a so-called three-beam method or a so-calledpush-pull method. The RF amplifier 63 outputs the RF signals to thedemodulating unit 67, while outputting the focussing error signals andthe tracking error signals to the servo controlling unit 64.

The servo controlling unit 64 generates servo signals for reproducingthe optical disc 10. Specifically, the servo controlling unit 64generates focussing servo signals, based on the focussing error signals,supplied from the RF amplifier 63, so that the focussing error signalswill be equal to zero, while generating tracking servo signals, based onthe tracking error signals, supplied from the RF amplifier 63, so thatthe tracking error signals will be equal to zero. The servo controllingunit 64 outputs the focussing servo signals and tracking servo signalsto a driving circuit, not shown, of the objective lens drivingmechanism, forming the optical pickup 62. This driving circuit actuatesthe objective lens driving mechanism, based on the focussing servosignals, to actuate the objective lens along the focussing directionparallel to the optical axis of the objective lens, while actuating theobjective lens driving mechanism, based on the tracking servo signals,to actuate the objective lens along the tracking direction perpendicularto the optical axis of the objective lens. The servo controlling unit 64actuates the motor 61 for rotationally driving the optical disc 10 inCLV or CAV.

When downloading desired contents data, the communication unit 65transmits the PUID data, read out from the loaded optical disc 10, whiletransmitting the selection data of the contents data he/she selected, tothe server device 40. The communication unit 65 is responsive to thecontents data download request to receive the contents data transmittedfrom the server device 40, and the PUID data, updated by the serverdevice 40.

The recording processor 66 applies signal processing for recording, tothe contents data and the PUID data, received by the communication unit65, to output the so processing data to the optical pickup 62. The PUIDdata, updated by the server device 40, is recorded in the managementarea 12 of the optical disc 10, by the light beam radiated by theoptical pickup 62, while the downloaded contents data is recorded in thedata recording area 13.

The demodulating unit 67 EFM-demodulates the RF signals, supplied fromthe RF amplifier 63, and outputs the output data to the error correctiondecoding unit 68. The error correction decoding unit 68 executes errordetection and error correction, based on the error correction codes,such as CIRC. When transmitting the PUID data to the server device 40,the error correction decoding unit 68 outputs the PUID data to thecommunication unit 65 and, when reproducing the contents data, the errorcorrection decoding unit 68 outputs the PUID data to the demultiplexer69. The error correction decoding unit 68 outputs the contents data tothe switching unit 73.

When reproducing the contents data, the demultiplexer 69 is suppliedwith the PUID data prior to reproduction of the contents data. Thedemultiplexer 69 separates the PUID data, input from the errorcorrection decoding unit 68, into UID data, PA data and MDC data. Thedemultiplexer 69 outputs the UID data and the PA data to the generatingunit 70, while outputting the MDC data to the comparator 71.

The generating unit 70 generates MDC data, from the UID data and the PAdata, input from the demultiplexer 69, using the hash function, tooutput the so generated MDC data to the comparator 71. Meanwhile, thegenerating unit 70 is similar in structure to that shown in FIGS. 6 to 8and hence is not explained specifically.

The comparator 71 compares the MDC data, extracted by the demultiplexer69, to the MDC data, generated by the generating unit 70, to determinewhether or not the two MDC data are coincident with each other. That is,if the UID data or the PA data have been manipulated, the MDC datagenerated by the generating unit 70 differs from the MDC data extractedby the demultiplexer 69. Thus, the comparator 71 compares the MDC dataextracted by the demultiplexer 69, to the MDC data generated by thegenerating unit 70 and, in case of coincidence of these two MDC data,determines that the access is that from an authorized user, to turn onthe switching unit 73. In case of coincidence of the two MDC data, thecomparator turns off the switching unit 73.

The D/A converter 72 converts the input contents data, that is digitaldata, into analog signals, and outputs the result to the output unit 74connected to the loudspeaker, earphone, headphone or to the monitor.

If it is determined by the comparator 71 that the MDC data extracted bythe demultiplexer 69 is coincident with the MDC data generated by thegenerating unit 70, the switching unit 73 is turned on by the comparator71 to interconnect the error correction decoding unit 68 and the D/Aconverter 72. If it is determined that the extracted MDC data is notcoincident with the generated MDC data, the switching unit 73 is turnedoff by the comparator 71 to disconnect the error correction decodingunit 68 and the D/A converter 72.

The operation of the data recording and/or reproducing device 60,constructed as described above, is hereinafter explained. First, indownloading the contents data, the optical pickup 62 accesses themanagement area 12 of the optical disc 10, being run in rotation by themotor 61, to read out the PUID data recorded in the management area 12.The RF amplifier 63 generates RF signals from an output signal of theoptical pickup 62, to output the so generated RF signals to thedemodulating unit 67. The demodulating unit 67 demodulates data tooutput the demodulated data to the error correction decoding unit 68.The error correction decoding unit 68 corrects the PUID data for errors.The PUID data, corrected for errors, are output to the communicationunit 65. Simultaneously, the communication unit 65 is supplied withselection data, specifying the contents data the user selected from theplural contents data stored in the server device 40. The selection dataare output by a controller, not shown, based on data input by the userwith the aid of an operating unit, such as plural operating keys, notshown, provided in the data recording and/or reproducing device 60. Thecommunication unit 65 sends the PUID data and the selection data,recorded on the optical disc 10, on which to record the contents data,to the server device 40.

In receiving the contents data corresponding to the selection data,transmitted in advance by the server device 40, the communication unit65 receives the PUID data, updated by the server device 40, and thecontents data corresponding to the selection data, to output these datato the recording processor 66. This recording processor 66 performssignal processing, necessary for recording, on these data, to output theresulting data to the optical pickup 62. The optical pickup 62 recordsthe updated PUID data in the management area 12 of the optical disc 10,kept in rotation by the motor 61, while recording the downloadedcontents data in the data recording area 13.

The operation in reproducing the contents data is hereinafter explained.First, when the operation for starting the reproduction is done by theuser acting on the operating unit, the motor 61 actuates the opticaldisc 10, loaded on the disc table. The optical pickup 62 thenilluminates a light beam to the recording layer of the rotating opticaldisc 10 to detect the return light beam reflected back from therecording layer, to access the management area 12 to read out the PUIDdata prior to the reproduction of the contents data specified by theuser. Based on the output signal from the optical pickup 62, RF signalsare generated by the RF amplifier 63 and the so generated RF signals aredemodulated by the demodulating unit 67. The PUID data, obtained onerror correction processing by the error correction decoding unit 68,are input to the demultiplexer 69. The demultiplexer 69 separates thePUID data into the UID data, PA data and the MDC data and outputs theextracted MDC data to the comparator 71 while outputting the UID dataand the PA data to the generating unit 70. The generating unit 70generates MDC data from the UID data and the PA data, input from thedemultiplexer 69, using the hash function, and outputs the MDC data tothe comparator 71. The comparator 71 has to verify whether or not theaccess is from the data recording and/or reproducing device 60 of a userowning the authentic optical disc 10. To this end, the comparator 71compares the MDC data, supplied from the demultiplexer 69, to thatsupplied from the generating unit 70, to verify whether or not the twocoincide with each other. The reason is that, if the PA data indicatingthe possible recording volume has been changed, the MDC data, output bythe generating unit 70, differs from the MDC data separated andextracted by the demultiplexer 69. The comparator 71 compares the MDCdata generated in the generating unit 70 to the MDC data extracted bythe demultiplexer 69. In case of coincidence of the extracted MDC dataand the generated MDC data, the comparator 71 turns on the switchingunit 73 to interconnect the error correction decoding unit 68 and theD/A converter 72 to permit reproduction of the contents data selected bythe user. In case of non-coincidence of the MDC data generated by thegenerating unit 70 and the MDC data extracted by the demultiplexer 69,the comparator 71 turns off the switching unit 73 to disconnect theerror correction decoding unit 68 and the D/A converter 72 to inhibitreproduction of the contents data.

In case of the coincidence of the two MDC data, the optical pickup 62accesses a preset address of the data recording area 13, to read out thecontents data specified by the user. The data read out by the opticalpickup 62 is demodulated and corrected for errors so as to be thenoutput to the D/A converter 72 via the switching unit 73 in theon-state. The contents data, converted into analog signals, are outputfrom the output unit 74.

The sequence of operations until the user downloads the desired contentsdata in the contents data distributing system 1 employing the serverdevice 40 and the data recording and/or reproducing device 60 is nowexplained with reference to FIG. 12.

If, in a step S1, the data recording and/or reproducing device 60accesses the server device 40, responsive to the user's operation, thedata recording and/or reproducing device 60 in a step S2 causes a listof downloadable contents data in a display unit, not shown, provided inthe device 60. If, in a step S3, the user acts on the operating unit,such as mouse or an operating key, to select desired contents data to bedownloaded, as he/she views the display on the display unit, thecontroller of the data recording and/or reproducing device 60 isresponsive to the input from the operating unit to generate selectiondata specifying the selected contents data.

If, in a step S4, the user acts on the operating unit, not shown, of thedata recording and/or reproducing device 60, the device 60 causes themotor 61 to run the optical disc 10 loaded on the disc table in rotationto cause the optical pickup 62 to read out the PUID data recorded in themanagement area 12. The RF signals, generated by the output signal fromthe optical pickup, are demodulated by the demodulating unit 67, whilethe PUID data, obtained on error correction by the error correctiondecoding unit 68, is output to the communication unit 65. Thecommunication unit sends the PUID data, recorded on the optical disc 10,on which to record the contents data, as well as the selection data forthe contents data, to the server device 40.

In a step S5, the communication unit 43 of the server device 40 receivesthe selection data and the PUID data, transmitted from the datarecording and/or reproducing device 60 through a communication network,such as network. The communication unit 43 outputs the PUID data to thedemultiplexer 44, while outputting the selection data to the readoutdetection unit 42. The demultiplexer 44 separates the PUID data, inputfrom the communication unit 43, into the UID data, PA data and the MDCdata, and outputs the MDC data to the comparator 46, while outputtingthe UID data and the PA data to the generating unit 41 and to the updateunit 47. The demultiplexer 44 outputs the PA data to the discriminationunit 48 in order to discriminate the recordable volume.

In a step S6, the server device 40 verifies whether or not thetransmitted PUID data has been manipulated. That is, the generating unit45 generates the MDC data, from the UID data and the PA data, input fromthe demultiplexer 44, using the hash function, and outputs the sogenerated MDC data to the comparator 46. Prior to reading out thecontents data corresponding to the selection data, the comparator 71 hasto verify whether or not the access is from the data recording and/orreproducing device 60 of a user owning the authentic optical disc 10. Tothis end, the comparator 46 compares the MDC data, supplied from thedemultiplexer 44, to that supplied from the generating unit 45, toverify whether or not the two coincide with each other. When the MDCdata generated by the generating unit 45 is coincident with the MDC dataseparated and extracted by the demultiplexer 44, the comparator 44determines that the access is from the data recording and/or reproducingdevice 60 of an authorized user, and outputs a readout permission signalto the readout detection unit 42. When the MDC data generated by thegenerating unit 45 is not coincident with the MDC data separated andextracted by the demultiplexer 44, the comparator 44 determines that theaccess is from the data recording and/or reproducing device 60 of anunauthorized user, and outputs a readout inhibit signal to the readoutdetection unit 42.

In a step S7, the discrimination unit 48 checks whether or not thecontents data specified by the user is downloadable with the current PA.If the contents data is downloadable, the discrimination unit 48 outputsa readout permission signal to the readout detection unit 42. If the PAdata is in shortage, the discrimination unit 48 outputs a readoutinhibit signal to the readout detection unit 42.

When supplied with the reproduction permission signal from each of thecomparator 46 and the discrimination unit 48, the readout detection unit42 in a step S8 retrieves and extracts the contents data correspondingto the selection data input from the communication unit 43, from amongthe plural contents data stored in the storage unit 41, to output the soextracted contents data to the communication unit 43.

In a step S9, the update unit 47 updates the PA data, depending on e.g.,the number of items of the downloaded contents data, and generates PUIDdata, transmitted to the data recording and/or reproducing device 60,from the updated PA data and the UID data, using the hash function, totransmit the so generated PUID data to the communication unit 43.

In a step S10, the communication unit 43 sends the updated PUID data,along with the contents data corresponding to the selection data, to theuser's data recording and/or reproducing device 60.

When the reproduction inhibit signal is supplied in the steps S6 and S7from the comparator 46 and from the discrimination unit 48, the readoutdetection unit 42 does not retrieve contents data corresponding to theselection data. The readout detection unit 42 does not transmit contentsdata to the data recording and/or reproducing device 60, either.

In a step S12, the communication unit 65 of the data recording and/orreproducing device 60 receives PUID data updated by the server deviceand contents data corresponding to selection data. In a step S13, therecording processor 66 performs signal processing for recording. Withthe optical pickup 62, the updated PUID data is recorded in themanagement area 12, while the contents data is recorded in the datarecording area 13.

If, when the contents data recorded in the data recording area 13 of theoptical disc 10 is to be reproduced, the user performs, in a step S14,the processing for reproduction by an operating unit, not shown,provided to the recording processor 66, the PUID data is read out in astep S15. That is, the motor 61 actuates the optical disc 10, loaded onthe disc table. The optical pickup 62 then causes a light beam to beilluminated on the recording layer of the rotating optical disc 10 todetect the return light beam reflected back from the recording layer toread out the PUID data recorded in the management area 12. Based on theoutput signal from the optical pickup 62, RF signals are generated andprocessed with demodulation and error correction to produce PUID datawhich then is input to the demultiplexer 69. This demultiplexer 69demultiplexes the PUID data into the UID data, PA data and the MDC datato send the MDC data to the comparator 71 as well as to send the UIDdata and the PA data to the generating unit 70.

In a step S16, the data recording and/or reproducing device 60 verifieswhether or not the PUID data transmitted thereto has been manipulated.That is, the generating unit 70 generates MDC data, from the UID dataand the PA data, input from the demultiplexer 69, using the hashfunction, to output the MDC data to the comparator 71. The comparator 71has to verify whether or not the access is from the data recordingand/or reproducing device 60 of a user owning the authentic optical disc10. To this end, the comparator 71 compares the MDC data, supplied fromthe demultiplexer 69, to that supplied from the generating unit 70, tocheck to see if the two coincide with each other. The comparator 71compares the MDC data generated in the generating unit 70 to the MDCdata separated and extracted by the demultiplexer 69. In case ofcoincidence of these two MDC data, the comparator 71 turns on theswitching unit 73 to interconnect the error correction decoding unit 68and the D/A converter 72 to permit reproduction of the contents dataselected by the user. In a step S17, the optical pickup 62 accesses apredetermined address of the data recording area 13, to read out thecontents data, in order to read out the contents data specified by theuser. The data read out by the optical pickup 62 is demodulated andcorrected for errors so as to be then output to the D/A converter 72through the switching unit 73 in the on-state. The contents data,converted into analog data, is output at the output unit 74.

If, in the step S16, the MDC data generated in the generating unit 70 isnot coincident with the MDC data extracted by the demultiplexer 69, thecomparator 71 turns off the switching unit 73 in the step S18 todisconnect the error correction decoding unit 68 and the D/A converter72 from each other to disable reproduction of the contents data selectedby the user to inhibit reproduction of the contents data.

In the present system 1, the MDC data is recorded in this manner in themanagement area 12 of the optical disc 10 along with the UID data andthe PA data, thus assuring facilitated detection even if the UID data orthe PA data has been manipulated. Since the PUID data is updated by theserver device 40 and not by the data recording and/or reproducing device60, it is possible to prohibit the PUID data from being manipulated byan unauthorized user. By recording the UID data along with the PA datain the management area 12, the PA data, that is the quantity ofconsumption by the user, can be managed.

In the above-described embodiment, the PUID data recorded in themanagement area 12 of the optical disc 10 is composed of the UID data,PA data and the MDC data, as shown in FIGS. 3 and 4. According to thepresent invention, the PUID data may also be composed of UID data,inclusive of the PA data, and MDC data, as shown in FIG. 13. In thiscase, the UID data inclusive of the PA data is the data identifying thesort of the optical disc 10, such as ID for 1,000 yen or an ID for 2,000yen. The MDC data is generated from this UID data inclusive of the PAdata using the hash function. In this optical disc 10, it can bedetected, by the server device 40 or by the data recording and/orreproducing device 60, whether or not the UID data inclusive of the PAdata has been manipulated, with the aid of the MDC data. Of course, datarelevant to the MAC data or the CRC data can be used in place of the MDCdata.

According to the present invention, the UID data can be recorded in themanagement area 12 of the optical disc 10, as PUID data, as shown inFIG. 14. In this case, the PA data is supervised by the server device 40supervising the present system 1. That is, PA data for each UID data ofeach distributed optical disc 10 is stored in the server device 40 and,when the user downloads the contents data by the data recording and/orreproducing device 60, the device 60 transmits the UID data of theoptical disc 10, along with the selection data of the contents data, tothe server device 40. The server device 40 retrieves the PA datacorresponding to the received UID data and verifies from the PA datawhether or not the contents data corresponding to the selection data isdownloadable. The server device 40 sends the selected contents data tothe data recording and/or reproducing device 60 only if the verifiedresults testify to downloading feasibility. Simultaneously, the serverdevice 40 updates the PA data corresponding to the UID data. In thiscase, the PA data is supervised by the server device 40, while no PAdata is recorded on the optical disc 10. Thus, there is no fear ofmanipulation of the PA data. Consequently, it is unnecessary for theserver device 40 to generate the authenticity data, such as MDC data,MAC data or CRC data.

It is similarly possible to record encrypted contents data in the datarecording area of the replay-only optical disc and to downloadencryption key data, used for decoding the encryption of the contentsdata, with the use of the above-described system 1.

In the foregoing description, the write-once optical disc and therewritable optical disc are taken as examples for the recording medium.Alternatively, the recording medium may be an IC card, employing asemiconductor memory, a disc cartridge, employing a magnetic disc or amagneto-optical disc, or a tape cassette, employing a magnetic tape.

INDUSTRIAL APPLICABILITY

According to the present invention, described above, manipulation ofdata recorded on the recording medium for indicating e.g., therecordable volume can be detected easily with authenticity data. Indistributing contents data, the identification-data-based recordablevolume can be managed by the communication device, such as serverdevice, by transmitting the identification data recorded on therecording medium to the communication device.

1. A method for reproducing data on a recording medium, the methodcomprising: reading out identification data from the recording mediumhaving at least content data and the identification data recordedthereon, said identification data including entity identification dataand first detection data, said first detection data: being generatedusing at least said entity identification data, and indicating whetheror not said entity identification data at least is authentic; generatingsecond detection data based on said identification data; comparing firstdetection data extracted from the identification data to the generatedsecond detection data; and permitting the outputting of said contentdata read out from said recording medium when results of the comparingindicate correlation of said first detection data with the generatedsecond detection data.
 2. The reproducing method according to claim 1wherein: when the results of the comparing indicate non-correlation ofsaid first detection data with the generated second detection data,preventing the outputting of the content data from said recordingmedium.
 3. The reproducing method according to claim 1 wherein: saididentification data includes volume data indicating a volume of datarecordable on said recording medium, said volume data generating saidfirst detection data along with said entity identification data; saidsecond detection data being generated based on the entity identificationdata of said identification data and on said volume data.
 4. Anapparatus for reproducing a recording medium, the apparatus comprising:a head unit for scanning the recording medium having at least contentdata and identification data recorded thereon, said identification dataincluding entity identification data and first detection data, saidfirst detection data: being generated using at least said entityidentification data, and indicating whether or not said entityidentification data at least is authentic; a signal processing unit forperforming signal processing for reproducing an output signal from saidhead unit; a generating unit for generating second detection data basedon said entity identification data; and a comparator for comparing thefirst detection data to the second detection data; and an outputtingunit for limiting the outputting of the output signal from said signalprocessing unit based on data derived from comparison results from saidcomparator.
 5. The apparatus for reproducing a recording mediumaccording to claim 4 wherein: when the first detection data correlateswith the second detection data, said comparator controls said outputunit to output the output signal from said signal processing unit. 6.The apparatus for reproducing a recording medium according to claim 4wherein: when the first detection data does not correlate with thesecond detection data, said comparator controls said output unit toprevent the outputting of the output signal from said signal processingunit.
 7. The apparatus for reproducing a recording medium according toclaim 4 wherein: said identification data includes volume dataindicating a volume of data recordable on said recording medium; saidgenerating unit generating second detection data based on the entityidentification data and further based on said volume data.
 8. Theapparatus for reproducing a recording medium according to claim 7wherein said generating unit generates second detection data using aunidirectional function.
 9. A method for recording a recording medium,the method comprising: transmitting identification data read out fromthe recording medium having at least entity identification data, volumedata indicating a volume of recordable data, and first detection datarecorded thereon, wherein said first detection data: is generated usingsaid entity identification data and said volume data, and indicateswhether at least said entity identification data and said volume dataare authentic; and recording updated identification data, includingupdated volume data, transmitted along with content data, on a recordingmedium.
 10. The method for recording a recording medium according toclaim 9 wherein said recording medium includes a content data recordingarea for recording said content data and a management data area forrecording said identification data, the method comprising: recordingsaid content data in said content data recording area; and recording theupdated identification data inclusive of updated volume data, in saidmanagement area.
 11. A data recording method comprising: reading outidentification data from a recording medium having at least saididentification data recorded thereon, said identification data includingentity identification data and at least first detection data, said firstdetection data: being generated using at least said entityidentification data, and indicating whether said entity identificationdata at least is authentic; transmitting read-out identification dataand selection data to a server device holding plural data; said serverdevice: generating second detection data based on said entityidentification data of said identification data, comparing generatedsecond detection data and first detection data and, reading out andtransmitting content data corresponding to said selection data in caseof correlation of the generated second detection data and the firstdetection data; and recording the transmitted content data on orreproducing the transmitted content data from said recording medium. 12.The data recording method according to claim 11 wherein said serverdevice prevents readout of said content data corresponding to saidselection data in case of non-correlation of the generated seconddetection data and the first detection data.
 13. The data recordingmethod according to claim 11 wherein said identification data includesvolume data indicating a volume of data recordable on said recordingmedium, said volume data being further used to generate said firstdetection data along with said entity identification data, said serverdevice generating said second detection data based on said entityidentification data of the identification data read out and on saidvolume data.
 14. The data recording method according to claim 13 whereinsaid server device generates said second detection data using aunidirectional function.
 15. The data recording method according toclaim 13 wherein said server device checks the volume data to see ifsaid volume is sufficient to record content data corresponding to saidselection data on said recording medium in case of correlation of thegenerated second detection data and the first detection data.
 16. Thedata recording method according to claim 15 wherein said server devicereads out and transmits content data corresponding to said selectiondata if said data volume data indicates that the content datacorresponding to said selection data is recordable.
 17. The datarecording method according to claim 16 wherein said server deviceupdates said volume data and transmits said identification datainclusive of updated volume data and the content data corresponding tosaid selection data.
 18. The data recording method according to claim 16further comprising: recording on said recording medium saididentification data inclusive of updated volume data and the contentdata corresponding to said selection data.
 19. The data recording methodaccording to claim 15 wherein said server device prevents readout ofsaid content data corresponding to said selection data if said volumedata indicates that recording of the content data corresponding to saidselection data on said recording medium is impossible.
 20. The datarecording method according to claim 11 wherein said identification datais read out from said recording medium, the first detection data isgenerated based on the entity identification data of said identificationdata, the first detection data is compared to the generated seconddetection data and the outputting of the content data from the recordingmedium is permitted when comparison results indicate that the firstdetection data correlates with the generated second detection data. 21.The data recording method according to claim 20 wherein: when thecomparison results indicate that the first detection data does notcorrelate with the generated second detection data, the outputting ofthe content data read out from the recording medium is prohibited. 22.The data recording method according to claim 20 wherein saididentification data includes volume data indicating the volume of datarecordable on said recording medium, said volume data generating saidfirst detection data along with said entity identification data, andwherein said second detection data is generated based on said entityidentification data of the identification data read out and on saidvolume data.
 23. The data recording method according to claim 22 whereinsaid second detection data is generated using a unidirectional function.24. A recording medium comprising: a data recording area where contentdata is recorded; and a management data area where there is recordedidentification data inclusive of entity identification data anddetection data generated using at least said entity identification data,said detection data indicating whether or not the entity identificationdata at least is authentic; wherein said management data area includesvolume data indicating the volume of data recordable on said recordingmedium, and wherein said detection data is generated using at least theentity identification data and said volume data.
 25. The recordingmedium according to claim 24 wherein said detection data is generated bya unidirectional function.
 26. A recording apparatus for a recordingmedium, said apparatus comprising: a head unit for scanning saidrecording medium having identification data recorded thereon, saididentification data including entity identification data and firstdetection data, said first detection data being generated using at leastsaid entity identification data and indicating whether or not saidentity identification data at least is authentic; a signal processingunit for performing signal processing for reproducing an output signalfrom said head unit; a communication unit for transmitting selectiondata and the identification data read out from said head unit and forreceiving transmitted content data corresponding to said selection data;a generating unit for generating second detection data based on saidentity identification data; a comparator unit for comparing the firstdetection data extracted from the read-out identification data and thesecond detection data generated by said generating unit; an outputtingunit supplied with the output signal from said signal processing unitand adapted for controlling the outputting of the output signal fromsaid signal processing unit based on comparison results from saidcomparator; and a recording signal processing unit for recording on saidrecording medium the content data corresponding to said selection datareceived via said communication unit via said head unit.
 27. Therecording apparatus for a recording medium according to claim 26wherein: when the first detection data extracted from the identificationdata read out correlates with said generated second detection data, saidcomparator controls said outputting unit to output the output signalfrom said signal processing unit.
 28. The recording apparatus for arecording medium according to claim 26 wherein: when the first detectiondata extracted from the identification data read out does not correlatewith said generated second detection data, said comparator controls saidoutputting unit to prevent the output of the output signal from saidsignal processing unit.
 29. The recording apparatus for a recordingmedium according to claim 26 wherein: said identification data includesvolume data indicating the volume of data recordable on said recordingmedium; said generating unit generates second detection data based onthe entity identification data of said identification data read out andon said volume data.
 30. The recording apparatus for a recording mediumaccording to claim 29 wherein said generating unit generates seconddetection data using a unidirectional function.
 31. The recordingapparatus for a recording medium according to claim 29 wherein saididentification data inclusive of updated volume data, transmitted alongwith said selected data, is recorded on said recording medium.